HTML5 mp3 playlist coffeescript jquery

gistfile1.coffee

jQuery ->
  playlistHandler()

playlistHandler = ->
  totalTracks = $(".song").length

  $(".song").click ->
    playSong($(this).attr('data-track'))
  
  $("#next").click ->
    currentTrack = $(".mp3player").attr('data-current')
    newTrack = +currentTrack+1
    if newTrack <= totalTracks
     playSong(newTrack)

  $("#prev").click ->
    currentTrack = $(".mp3player").attr('data-current')
    newTrack = +currentTrack-1
    if newTrack > 0
      playSong(newTrack)

  $(".mp3player").bind "ended", ->
    currentTrack = $(".mp3player").attr('data-current')
    newTrack = +currentTrack+1
    if newTrack <= totalTracks
      playSong(newTrack)

  playSong = (trackNumber) ->
    song   = $("a[data-track=#{trackNumber}]").attr('data-song')
    track  = $("a[data-track=#{trackNumber}]").attr('data-track')
    artist = $("a[data-track=#{trackNumber}]").attr('data-artist')
    title  = $("a[data-track=#{trackNumber}]").attr('data-title')
    $(".mp3player").attr('src', song)
    $(".mp3player").attr('data-current', track)
    $(".mp3player").attr('autoplay', "true")
    $("#nowplaying").text(artist + ": " + title)
    return false